The double-meaning title of Young Adult—the new Paramount comedy-drama re-teaming Diablo Cody and Jason Reitman, the writer and director, respectively, of Oscar-script sleeper Juno—refers both to the literary niche of novels aimed at teenagers and to Mavis Gary (Charlize Theron), who in our present world of maturity-challenged baby-men and Apatow avatars is a woman who, at 37, is still a young adult.

That's a different thing with women than with men. With men, you get Seth Rogen and 40-year-old virgins. With women, you get a divorced and disillusioned former "psychotic high-school bitch" who decides the only way to grow up is to follow her bliss and destiny and all that stuff and marry her old high-school boyfriend. Who's already married. With a kid. Back in her old hometown.

No problem. That small-town family of yours? "We can beat this thing together," she supportively assures him with misplaced reasonableness.

An amazing little movie with a Streep-wise performance by Theron—who impossibly, impeccably, gives her character humanity—Young Adult cost a modest $12 million to make and was shot in 30 days. Like The Wrestler or Crazy Heart or even Reitman's own Up in the Air, it's one of those small end-of-year films that, rightfully, charms audiences and Academy voters alike. OK, maybe we're kvelling—but how many movies with such a distinctly Midwestern milieu make you kvell?

And it is very Midwestern, though shot mostly in upstate New York and on Long Island. Mavis, who ghostwrites the “Waverly Prep” young-adult book series, has transplanted herself from dinky, fictional Mercury, Minnesota, to "the Mini-Apple"—Minneapolis, about as mini an apple as you can get. But it's still big-time to the likes of Mavis' old flame, Buddy Slade (Patrick Wilson); his wife Beth (Elizabeth Reaser, way different from Twilight's Esme Cullen); and Matt Freehauf (Patton Oswalt), the bitterly cheerful, toad-like nonentity who had the locker next to hers way back at school, and who now becomes Mavis' drinking buddy while she plots to win Buddy, since what's she going to do? Stay at the hotel all day?

We spoke separately with Theron, Cody and Reitman as they each described how they committed Young Adult-ery.

Film Journal International: There is, to me, a devastating moment in this movie, where Mavis is sitting at her parents' kitchen table, back in old hometown, and just casually tosses off this sudden, cold, hard truth about herself, and her parents [Richard Bekins, "L.A. Law"'s Jill Eikenberry] pooh-pooh it, like, "Yeah, yeah, whatever you say."

Diablo Cody: That's something that I felt growing up in the Midwest and living in Chicago and Minneapolis—that people are less candid about things like that. And I wanted to show that she came from a family that wasn't super-expressive about emotions. It's also just a hilarious moment because I think we've all been there where we're spilling our guts to somebody and they completely blow it off because it's a difficult truth or it's something that they don't necessarily want to hear.

FJI: You mention "hilarious," but for the New York audience at the screening I attended, it was more like a heavy, dramatic moment. There was sort of a sympathetic gasp when her parents shrugged it off.

Cody: That's so interesting. [pause] It's true—it is kind of horrifying, and it is maybe a moment where you feel sympathy for her. Most of the times that I've sat in on a screening, that line's gotten a laugh, but it's interesting to think that people would interpret it as kind of a tragic thing.

Charlize Theron: When her mother laughs it off, you realize there wasn't a lot of intimacy. People say, "Oh, look, Mavis came from a nice family," but it's one that didn't check in emotionally with her at all.

FJI: Charlize, you came from what you've talked about in the past as, to put it gently, a dysfunctional family. [On June 21, 1991, in Theron's native Benoni, South Africa, mom Gerda shot and killed Theron's physically abusive, alcoholic father Charles in self-defense, facing no charges afterward.] Mavis drinks pretty heavily throughout the movie. Did your past make it harder to create this character, bringing up bad stuff, or did it actually make it easier for you to understand her?

Theron: My past didn't make it easy or hard. When I'm figuring out a character, for me it's easy, since once I say yes to something, I become super-obsessed about it—and I have an obsessive nature in general. How I want to play it starts at that moment. It's a very lonely, internal experience. I think about [the character] all the time—I observe things, I see things and file things [in my head], everything geared to what I'm going to do. I'm obsessed with the human condition. You read the script and become obsessed with [Mavis'] nature, her habits. When the camera rolls, it's time to do my job, to do the honest truth. You can't do that part of the [character-creation] work when you're [in the middle of] making the film. At least I can't.

Cody: I think [Mavis' drinking] was a difficult balance for Jason to strike, because he would talk about "How much drinking is too much?" There was originally, I think, even more booze in an early cut and it just got to be too much.

FJI: Diablo, what's that thing Mavis orders that she used to drink in high school, Hard Jack? Is that something real from when you lived there?

Cody: No, I made it up. I wanted it to be like a cider. Mavis is really immature, and Hard Jack is what she and Buddy used to drink in high school, when kids drink sweet crap.

FJI: Oh, like Mike's Hard Lemonade.

Cody: Exactly. Something like that. I love the idea that she's so convinced that she and Buddy are going to pick up exactly where they left off that she orders the same drink and he's just like "Why would I drink this?"

FJI: People in her hometown think Mavis is living this glamorous big-city life, but she just has kind of an average apartment in an anonymous high-rise in Minneapolis.

Cody: I dunno. There was a time in my life where I really aspired to having like a nice condo in a cool part of town. That's all I could hope for. Did you think her place was crappy?

FJI: No, I just thought it was a small, nondescript apartment.

Cody: I know what you're saying. But for the people from her hometown, you know, Minneapolis is a relatively big city. And she moved there, and she's a writer and she owns her own place. That's fairly impressive in some circles.

FJI: It's interesting because just about every movie uses New York or Chicago or some city like that where the small-town girl winds up, but you made a very deliberate choice to put her in Minneapolis.

Cody: I wanted this movie to happen on a realistic personal scale, and I felt that people who are from a tiny community in northern Minnesota would be impressed by her living in the Twin Cities. And that's part of what makes the situation so toxic: that they are too easily impressed.

Jason Reitman: When I think about [Mavis'] life in Minneapolis, I think about her as a writer, I think about her driving that [BMW] Mini, I think about that high-rise apartment—that they're all desperate grabs toward having a life. But the truth is she feels empty. I think her life made perfect sense in high school and ever since then she's just gotten off the path.

Theron: The social structure that that whole [high school] world is about is everywhere—in Minnesota, in Japan, doesn't matter. You go to school at that age and there are all these little cliques. Whether you have an actual prom king and queen doesn't matter. She knew how to navigate there, but [she doesn't do] so well outside [high school]. It makes sense she'd be writing [books] about that world.

FJI: Did you read young-adult novels growing up?

Theron: I didn't grow up with young-adult books. Wish I did. I can't imagine being a teenager [today] and not reading that stuff. It's so geared toward that kind of mindset, it's amazing. No 16-year-old should be reading Bukowski.

FJI: Talking about young-adult novels: Diablo, in 2009, you were going to write and produce an adaptation of "Sweet Valley High" for Universal.

Cody: Oh my gosh. I wish I could tell you what's going on with that.

FJI: Give me a hint.

Cody: I will say that as recently as yesterday there are very exciting and very newsworthy developments concerning "Sweet Valley High." But I am still sworn to secrecy.

FJI: You can't say it's green-lit yet.

Cody: It is not green-lit per se. Let's just say that work never stopped on it. We have been moving forward with it and I am very excited about it.

FJI: Let's talk about how the film came together. Diablo, you've said Mavis is partly based on you. She lives in Minneapolis, as you did for a time, so what part of you is she based on besides the living-in-Minneapolis part?

Cody: This common question I would get at Q&As or press junkets or what-have-you was: "Why are you so fixated on [movies about] adolescents?" [I began wondering:] Am I stunted somehow? And so as I thought about my own life, I thought, "Gosh, that would be a great character—a woman in her 30s who writes young-adult fiction and does in fact cling to deluded teenage fantasies in her real life, and is obsessed with recreating her teenage years come hell or high water."

FJI: So you created Bizarro Cody.

Cody: Exactly. Like this is as bad as it could get. In the end I don't really relate to Mavis. I don't think that I have the same issues that she has. I have to say, I don't really relate to [Buddy's wife] Beth, either. Beth is just such a fundamentally decent person—I think I'm a lot more selfish than she is. She's just this joyous drummer in a [local pickup] band and she seems like she's such a wonderful, supportive wife to Buddy, and I can understand why that annoys Mavis. I actually created the character of Beth before I was a mother myself [of son Marcello, with husband Dan Maurio, born July 27, 2010].

FJI: Getting back to some of the chronology: How did Jason get involved?

Cody: Jason and I are really close friends, and so I tend to show him everything that I write, regardless, and he sends me his scripts as well. We just like to get each other's opinion. So I sent it to him without any expectations—I just said, "When you get a chance, can you read this? Let me know if you think it's any good." And he read it and he liked it, and I think that was the end of it for a little while. And I went back to work on it and I produced a couple more drafts, and then I think I sent it to him again and he said that it seemed like something he might want to direct.

Reitman: I have a film I'm going to be making next year called Labor Day and it got pushed and a window opened up and I had the opportunity to make this.

Cody: Your favorite director is going to make the movie, he's going to do it in, like, the next six weeks, and he's putting this Oscar-winning actress in the lead. I just thought, "I must be dreaming!" It was great.

FJI: Then Patrick Wilson got cast.

Theron: I'm a massive Patrick Wilson fan—one of my favorites of his is his performance in Little Children. And I had a word with Jason about wanting him to be in the movie. He's one of those actors that no matter what he's in, he's committed—you don't see him through the character.

Reitman: He read for it and he was wonderful. Charlize and I certainly talked about who was going to play that role, and she wanted him to have the role and I couldn't agree more.

Theron: Patton and I met on a table read-through after I said yes to the film, and after [Jason] saw us read together, he said he liked what he saw and what did I think and I said I love him [for the role] and he offered him the part.

Cody: I don't think Jason was super-familiar with the work Patton had done on [Cody's Showtime series “United States of Tara,” in which he played a supporting role]. I remember Jason saying to me, "How do you feel about Patton Oswalt?" and I said, "Well, obviously I love him—he's on my show," and Jason was like "Oh yeah." It was almost like a coincidence. It's just exciting to see this happening for him. Because everybody knows him as this brilliant comic, but he's a brilliant actor. And he was [Remy in] Ratatouille, which is just epic.

Reitman: Patton is the secret weapon of this movie. I really love this movie as a romance between them. They have undeniable chemistry and it's kind of heartbreaking that they can't wind up together. Chemistry is one of those magic, ethereal things that just happens. But when they sat down for a table read at my house, you could just read their chemistry. It was just off the charts.

Theron: I think the beauty and the complexity of this film is that it's so unexpected and so different. The combination of Jason and Diablo and what they represent and what I represent—we set out to do something people wouldn't expect of us. I think we've been really smart with pop-up screenings and introducing it to the right audiences, people open to seeing something different. This movie is going to succeed on word of mouth.

Reitman: But it's a film that's going to have to live on the pedigree of the filmmakers and stars and on people talking about it. I really hope that people have the experience I expect they will have when they watch it—that it'll be a little bit jarring, it'll be funny and it's gonna push them to think about themselves and their friends and they’re going to want to talk to friends about it. For all the reasons that are going to make it a little uncomfortable to watch, it'll thrive.